Mixed fertilizer



Patented May 10, 1932 UNITED STATES Eli-H81 KEYSSNER AND HELIUT MENGDEHL, OF LUbWIGSElm-ON-THE-BEIHE,

GERMANY man FERTILIZER no Drawing. Application filed Iu1y28, 1980, Serial at. 471,411, and it Germany August a, 19:29.

The present invention relates to improvements in mixed fertilizers containing urea. For fertilizing purposes use is often made in practice of mixtures of organic waste materials of animal or vegetable origin with fertilizing salts. When 1n such a case use is made of urea or salts containing urea in mixture with such vegetable material as contains the ferment urease which decomposes urea, generally the stability of the mixture in storage is decreased because the urease splits ofi ammonia from the urea and thus gives rise to losses in nitrogen.

We have now found that mixtures of vegetable material initially containing ur'ease with urea, or fertilizers containin which .arestable in storage, can be 0 tained by exposing the vegetable material contain ing ureaseto an elevated temperature of at lease 80 C. The temperature employed in this treatment should as a rule not exceed 150 0., since otherwise valuable plant nutrients are liable to suffer undesirable decomposition. The time necessary for the treatment depends on the temperature employed and usually varies between a quarter of an hour and one hour.

be effected for example by means of hot air or of steam or both and may be effected either before the vegetable material is mixed with the urea, or fertilizers containing urea, or shortly after the mixing has been effected. By the treatment in accordance with the vention the vegetable material initially containing urease is so modified that thereafter it has lost its decomposing action on urea.

The following examples will further illustrate, how the present invention may be carried out in practice, but theinvention is not restrictedto these examples. The parts are by weight.

Example 1 Soy bean meal freed from oil is heated for hour to about 120 C. and then mixed with urea, preferably in the proportions of 75 arts of soy bean meal to 25 parts of urea. e mixture does not split of! ammonia, even when kept in astrong'l'y moist state, whereas 60 a similar mixture prepared from soy bean urea,

The heat-treatment may resent inv meal which has not been subjected to the heat treatment, disengages ammonia due to a decomposition of the urea.

In a similar manner other vegetable materials containing urease, as for example jack beans (canavallia ensiformis), sesamum, peanuts (arachis hypogaea), castor beans, or hemp-seed, may be rendered suitable for mixing with urea.

Example 2 soy bean meal freed from oil which has been heateg to a temperature between 80 and 150 g 3.- Mixed fertilizers comprising about 25 to 40 parts of urea and to parts of a vegetable material initially containing urease and which has been exposed to a temperature between and 150 C.

ourhands.

ERNST KEYSSNER. HELMUT MENGDEHL'. 

